zsh_completion: use $_hg_remote_opts after it is defined

Authored by av6.

Description

zsh_completion: use $_hg_remote_opts after it is defined

Before this patch, zsh wouldn't complete --ssh, --remotecmd or --insecure for
hg clone.

While at it, replace --uncompressed by --stream.

Differential Revision: https://phab.mercurial-scm.org/D5140